Feed preparation for furnace black production



N0V 2, 1954 c. J. HELMl-:Rs

FEED PREPARATION FOR FURNACE BLACK PRODUCTION Filed Jan. 2, 1951 United States Patent cOtitice FEED",PREPARATION' FOR FURNACE BLACK 'PRODUCTION Carl J. Helmersy-BartlesvillegOkla., Hassignor toPhllips Petroleum Compauygacorporationof Delaware` j ApplcationJanuary :2, 1951; Serialy No. 203,988 r 6 Claims. (Cl. 196,-14.26)

This invention.relatesf-toea solvent.-extraction= process.

of. an` improvedoilffeed Tand iproducing furnace carbon black therefrom.

In a solvent extraction'operation for the separation vof carbons, two liquid phasesare'obtained. Solventsfre- .quent 4times are specilically heavier than :the hydrocarbon .oils being treated,f.and-under ysuch conditions anfextract phase ywill be'removed-fromthe bottom of -the contacting zone. The nonaromatic:hydrocarbons l'with some solvent .in solution risein the-heavier lsolventandvare removed "from ythe top of .the vessel.- A commonmethod foi-'the separationof dissolved-solvent yfrom the rathnate.v phase is by distillation in which the solventiswithdraWn-from the `top'of-thedistillationrvessel as overhead product. Thisl 'solvent vapor may becondensed and returned to Fthe'ex- 'traction vessel as a portion of thevsolvent.y "The 'rainate oil'. s thentfwithdrawn fas 'bottomsr from 'this distillation vessel The' Vsame general operationfis. frequently used `for .the recovery 'of `the solvent" from'` the extract phase vin lwhich the extract oilris withdrawnfrom the'distillation column as bottomsandi the.' solvent istaken overhead-as vapor.` This solvent vapor is likewise: condensed andrefcycled as the main portion ofthe ysolvent to the extraction column.

Whenl distillingl the'.` solvent. from thelextra'ctfphase Vand the extract toil'4 contains aromatic-hydrocarbons boiling, Vfor examplefbetween 350and 4001F.,-a veryf'signicant amount, sometimes as muchas ten per cent,A of the'sellowboiling aromatic hydrocarbons has ^heretofore-so1netimes passed overhead in' this distillation column ywith Athelnormally lower boiling 1 solvent. When"usingacertain-cxtraction solvents, thisirregularity in solvent recovery from the extract phaseoccurs, .and'while using other'solvents,

Vtract oil is greatlyxenhanced; and, for'this" reasonfthe lowerzboilingf portion of such an extractl oil-tends to In one aspect it relates toa process for recoveringsolvent from anV extract phase in an operation for the production `aromatic from nonaromaticfgasoil boiling range hydro-- vaporize at a faster.` ratethanwouldtbe expected.` tIn other words, the 'activity ofithe'lowl boiling'lportion of the A extract oil in 'the presence 'ofl the high concentration yof solvents .is highr and,1fory thissreason,` some*A extracttioil actually passes overhead' from the. extract oildistillation known commercial. distillation' columns arefemployed. Upon condensationy of-the overhead vaporsgf'thisextract oil also condenses and remains. insolution 1in .the'solvent Upon 'introduction vof this condensateiinto the original extraction column as solvent,faromatic oilflis introduced or recycled. into this. columnfatlapoint -nearlthe rainate outlet. A largeportionof lthe aromaticL oil thusrecycled is extracted from Ythe. solvent by lthe high concentrationof rainateyin the upper endnof the extractionJcolumnand ration.

I have nowfound'za. combination*processwwhereby catcolumn with the solvent-vapors even-when Ithevery-fbest 1 alytic gasv oils. obtainedfrorrncatalyticcracking operations Patented Nov. 2, 19.54

Aand;having-:the low-boiling.;componentsipresentfmay be :.proc'essedto ,produce fa. hightfyeld. ofv r.10W` "anilneg ypoint =furnace carbo11'-black.--feed: without@encountering4 azeotroping vdiiiculties-irrthe extract recoveryzone. Bypthe method of this invention;asfeedq-hydrocarbon.is fractionyated toI segregate those constituents, ,boiling below about 450 '.1 F., V`'solvent extracting thee-higher boiling material with .-thelsolvent-to produce a low: aniline point extract phase, removing #solvent `ffrom *the-s extract phase aand f blending togetherfzthe low-boiling fraction` originally, separated' andv `the extractoil produced-by: theextraction. VBy this processl a, higher; yield ,ofspeciicationfeed vstocks for producing carbon black is obtainable by extracting-L toa lower-thanrspecication; aniline` point `and-` blending with the. -higherfthan-specilication-laniline point material. The disadvantage .of azeotrope formation in the solvent recovery step andl contamination Aof rainatefoilis alsogavoided. An object yofy `my invention is to .d'evise a process for the production of :a flow* aniliney point lgas Voil lfeedstock for use in yproducing furnace type carbon black.

Anotherobject';of'my-1invention isyto devise sucha process in :whichY-the ,=yield-,0f carbonv blaclcfeed` stock oils.` is ,greater-than obtainedybywnormalv methods.

Anotherobject of my inventionsisrtadevise a` process -.which is-simpleninoperation for-,thei production ofvsuch a carbon black ,feedf stock.`

I Still another objectyofzmy3invention,is-.todevise such a -process whichy is Vcharacterized by.low operating: costs. Still -other l objects and advantages'fof Amy invention will l be realizedfupon reading thefollowingspecification which, taken -withthe Zattachedfdrawinggtorms.` a` part of'crhis specification.

The drawing represents oueembodiment .offapparatus parts; which` may 'be fused-in 'practicing the 4process of my invention.

In the` drawingf.referencenumeralv 1 refers lto lthe solvent extractioncolumn of conventional type. 'Reference ynumerals 12, 21,.-and 31refer to distillation` columns in which the; feedstock, extract phase ,y andraflinate phase, respectively, are distilled. Elements 44 and 1451are vcarbon black, producing furnaceswhile elementSSx is a means for separating carbon black from the gaseouseluentin .the-furnaces, foriexample, bag `ilters; electro-precipitator, etc. The-dstillationcolumn.12. is equipped-with a reuxing coil.,15-and\areboilingfcoil16. lStills'21 and 3l v are4 provided with reiluxiugcols24 and 34, respectively, and-fwithvreboiling coils 2,5:an.d"35,' respectively...` Inlet 'and out-let connectionsfto these several 4vessels with 'interconnecting` pipes-'willbe fidentied in ythe' yfollowing-paragraphs whichdescribes? theoperation of my process.

ln the operation of the processof my invention, a catalytic gasoil-.boiling betweenfabout.` 3504l0 uF. and 750` F. 4.(AS'l-Mdistillationlis conducted from a source, not shown, through aline 11-to the fractionation zone 12. This fractionation zone'v is so.; operated 4that constituents of the-gas oilfboiling below about450 F. are separated Aand lremoved 1.'hrough'-line` 13y as. an'overhead product. The gas oil constituents Vboiling higher than 450 F. are removedfasa bottoms product-through@ line 14 andare conducted aftercooling infa cooler 10 to the extraction :Lone7 1. Solvent, which inithis embodiment is considv ered to be -=specif`1cally 'heavier than :thhydrocarbon oil charged through line 14, is introduced: into'extraction colllrnI-r1-througha solvent-charge linec4. `The charge oily `to f this: column :tends towrise .upward therein -while the heavy :solvent -followssa downward course.` Accordingly, .the ratlinatephasedsremoved--via-overheadline 3 and is passedon through. this line to theraflinate oil recovery column 31.v AThis. columnis.operated` in such'a 4manner 'that the solvent in solution in the raffinate oil is distilled overhead through vline, 32. as. a vapor which .is condensed incondenser` 36j and the condensed. `solvent lowson through line. 4 to the extraction columnl. The ranate oil is' removed from the bottom of this `ratlinate, still`31 Hthroughfa line'33'and is passed to subsequent storage for use as .desired. y

` The extract -phase -is withdrawn from' the extraction wcolumn lithrough a line-'2 andf is introducedinto about `the Amid-portion ofthe extract -recovery-column 21; j This :columnisf operated insu'ch a jmamerlthat the solventi-is irdistilled overheadtasaafvapor through -line22. ``rFhisidistillate vapor passes on through a portion of line 32, is condensed along with the vapors from the raffinate column 31 in condenser 36 and the combined condensate is passed on through line 4 to the extraction column 1. The extract oil is removed from the extract recovery column 21 through a bottoms drawoff line 23. Oil from this line is combined with the overhead distillate vapors from still 12. This combined oil stream is passed on through line 41 through the heat exchanger 61 for temperature adjustment and then into the carbon black producing system indicated in the drawing by reference numeral 40. Makeup solvent may be introduced into the system through a line 4A, as needed.

Apparatus for making carbon black with the herein produced oil feed stock and methods for operating the apparatus are described in U. S. Patents Nos. 2,375,795 and 2,375,796.

Such apparatus broadly consists of cylindrical furnaces 44 and 45. These furnaces are equipped with oil charge lines 42 and 43, respectively. Feed oil, before being introduced through lines 42 and 43 into the furnaces, is preferably vaporized in the temperature adjusting or heater apparatus 61. A line 46 is provided for supplying air, from a source not shown, for burner 48 in furnace 44 and to line 47 which in turn supplies air to burner 49 for furnace 45. In case it is desired to introduce a fuel gas also to the burners 48 and 49, a line 50 is provided for conducting fuel gas from a source, not shown, to the individual lines 51 and 52 which in turn supply fuel to burners 48 and 49, respectively. Effluent gases from furnace 44, conducted therefrom through conduit 53 are cooled by water from a water spray 55, and are conducted therefrom on through conduit 57 to a carbon black separating apparatus 58. Effluent gases containing carbon black in suspension are removed from furnace 45 through conduit 54, are cooled by water from a water spray 56, and the cooled eiuent is passed on through the line 57 to the carbon black separating apparatus 53. This carbon black recovery apparatus may be apparatus of conventional design such as, for example, an electric precipitator, cyclone separators, bag filters, or combinations of each. Conduit 59 is for discharge of gases after carbon black has been recovered. Conduit 60 isintended for conducting the separated carbon black from the recovery apparatus 58 to storage, pelleting, or subsequent use as desired.

When furfural is used as the extraction agent in the extraction zone 1, and a catalytic gas oil of a boiling range from 410 to 750 F. is used as the charge oil, the solvent to feed ratio may be selected from between the limits of 0.5:1 and 5:1. The temperature of con-A tacting is usually within the range of 50 to 160 F. The extract oil produced from a catalytic gas oil feed of 125 to 160 F. aniline point is usually in the range of minus 75 to plus 20 F. The extract oil, of course, upon blending with the components of the catalytic gas oil boiling below 450 F., is increased in aniline point to equal that required by specifications of carbon black feed stock.

The particular operating conditions for the several stills will need be that merely required to give effective separation between the desired components. Still 12 is operated at such refuxing and reboiler temperatures as will give an overhead vaporous product having an end boiling point of about 450 F. The several temperatures maintained in stills 21 and 31 are such as required to distill overhead the solvent from the extract and the rainate phases.

Another solvent which tends to form an azeotrope and adversely affect solvent recovery in the extract distillation still and the rafiinate distillation still is methylcellosolve. This process is also applicable to the use of any other solvent which shows azeotrope forming tendencies with any kof the lower boiling components of the gas oil charge stoc Apparatus used for carrying out the process of my invention may, for the most part, be constructed of materials available commercially. Such auxiliary apparatus as pumps, valves, pressure gauges, recording apparatus, temperature indicating and recording apparatus, pressure and temperature controllers, or ow controllers, are not shown nor described for purposes of simplicity. The necessity for the use and the installation and operation of such auxiliary apparatus is well understood by those skilled in the art. It will be realized that the operation 4 conditions of my process may be varied according to the specification of the product desired to be prepared.

The above described flow diagram is given for purposes of illustration and should not be regarded as limiting the invention, the scope of which is set forth in the following claims.

I claim:

l. A process for producing an improved furnace carbon black feed stock in increased yield based on the feed stock charged to the process comprising the steps of .subjecting a catalytic gas oil feed stock having a boiling range from a temperature below 450 F. to about 750 F. and obtained from a catalytic cracking operation to a distillation operation to produce an overhead distillate product boiling up to about 450 F. and a bottoms product boiling from about 450 F. to said 750 F., solvent extracting said bottoms product with furfural to produce a raffinate phase and an extract phase, recovering solution furfural from the rafiinate phase, subjecting the extract phase to a distillation operation and producing an overhead product comprising furfural and a bottoms product comprising a gas oil fraction boiling from about 450 F. to 750 F., combining this latter gas oil fraction with the aforesaid overheadY distillate product boiling up to about 450 F. to produce an improved furnace carbon black feed stock in increased yield.

2. A process for producing a furnace carbon black feed stock having a predetermined aniline point and of increased yield based on the feed stock charged to the process comprising the steps of subjecting a catalytic gas oil feed stock boiling from about 400 F. to 750 F. and obtained from a catalytic cracking operation to a distillation operation and recovering therefrom an overhead distillate boiling up to about 450 F. and a kettle product boiling above about 450 F., solvent extracting said kettle product with furfural to produce a raffinate phase containing solution furfural and an extract phase, separating the raffinate hydrocarbons from the furfural in the raffinate phase, returning the separated furfural to the extraction operation and recovering the separated rafiinate hydrocarbons as one product of the process, subjecting the extract phase to a distillation operation and separating therefrom an overhead distillate of furfural and a kettle product containing a low aniline point fraction of said gas oil boiling above about 450 F., returning the separated furfural to the extraction operation, combining this low aniline point fraction of gas oil boiling above about 450 F. with the recovered overhead distillate boiling up to about 450" F. to produce said oil of predetermined aniline point and in increased yield.

3. A process for producing a furnace carbon black in increased yield and a nonaromatic gas oil cracking stock from a catalytic gas oil feed stock boiling from about 400 F. to 750 F. and obtained from a catalytic cracking operation comprising the steps of subjecting said catalytic gas oil feed stock boiling from about 400 F. to 750 F. and obtained from a catalytic cracking operation to a distillation operation and recovering therefrom an overhead distillate boiling up to about 450 F. and a kettle product boiling above about 450 F., solvent extracting said kettle product with furfural to produce a raffinate phase containing some solution furfural and an extract phase, separating the rafi'inate hydrocarbons from the furfural in the raffinate phase, returning the separated furfural t0 the extraction operation and recovering the separated rainate hydrocarbons as said nonaromatic gas oil cracking stock as one product of the process, subjecting the extract phase to a distillation operation and separating therefrom an overhead distillate of furfural and a kettle product containing a low aniline point fraction of said gas oil boiling above about 450 F., also returning this latter furfural to the extraction operation, combining this low aniline point fraction of gas oil boiling above about 450 F. with the recovered overhead distillate boiling up to about 450 F. and subjecting this combined oil to furnace carbon black producing conditions, and recovering quality carbon black from the efuent of the carbon black producing operation and in increased yield based on the feed to the carbon black producing operation.

4. The process of claim 3 wherein the furfural-to-oil ratio in the extraction operation is maintained between the limits of 0.5:1 and 5: l.

5. In a process for the solvent extraction of a gas oil having a boiling range from about 350 to 750 F. and

produced from a catalytic cracking operation with a solvent having a boiling point below the boiling point of the lowest boiling gas oil constituents to produce an oil having a predetermined aniline point and of increased yield based on the gas oil charge stock to the process wherein upon distillation of the extract phase for solvent recovery the solvent exhibits azeotroping tendencies with constituents of said gas oil boiling below about 450 F. and said constituents tend to distill overhead and to contaminate the recovered solvent, a method for carrying out this process without losing extract hydrocarbons with the overhead solvent from the extract still comprising the steps of subjecting said gas oil to a distillation operation and producing an overhead distillate product boiling below about 450 F., and a bottoms product boiling from about 450 F. to 750 F., solvent extracting the bottoms product with said solvent and producing a raffinate phase and an extract phase, recovering solution solvent from the ranate phase, subjecting the extract phase to a distillation opera tion and producing an overhead product of solvent free from extract hydrocarbons and a bottoms product of extract oil, combining this extract oil bottoms with the aforesaid overhead distillate product boiling below about 450 F. to produce said oil of predetermined aniline point and in increased yield.

6. The process of claim 5 wherein the solvent is a solvent selected from the group consisting of furfural and methylcellosolve.

References Cited in the lile of this patent UNITED STATES PATENTS Number Name Date 2,128,885 Poole Aug. 30, 1938 2,507,861 Manley May 16, 1950 2,516,134 Molique July 25, 1950 2,608,470 Helmers et al. Aug. 26, 1952 

1. A PROCESS FOR PRODUCING AN IMPROVED FURNACE CARBON BLACK FEED STOCK IN INCREASED YIELD BASED ON THE FEED STOCK CHARGED TO THE PROCESS COMPRISING THE STEPS OF SUBJECTING A CATALYTIC GAS OIL FEED STOCK HAVING A BOILING RANGE FROM A TEMPERATURE BELOW 450* F. TO ABOUT 750* F. AND OBTAINED FROM A CATALYTIC CRACKING OPERATION TO A DISTILLATION OPERATION TO PRODUCE AN OVERHEAD DISTILLATE PRODUCT BOILING UP TO ABOUT 450* F. AND A BOTTOMS PRODUCT BOILING FROM ABOUT 450* F. TO SAID 750* F., SOLVENT EXTRACTING SAID BOTTOMS PRODUCT WITH FURFURAL TO PRODUCE A RAFFINATE PHASE AND AN EXTRACT PHASE, RECOVERING SOLUTION FURFURAL FROM THE RAFFINATE PHASE, SUBJECTING THE EXTRACT PHASE TO A DISTILLATION OPERATION AND PRODUCING AN OVERHEAD PRODUCT COMPRISING FURFURAL AND A BOTTOMS PRODUCT COMPRISING A GAS OIL FRACTION BOILING FROM ABOUT 450* F. TO 750* F., COMBINING THIS LATTER GAS OIL FRACTION WITH THE AFORESAID OVERHEAD DISTILLATE PRODUCT BOILING UP TO ABOUT 450* F. TO PRODUCE AN IMPROVED FURNACE CARBON BLACK FEED STOCK INCREASED YIELD. 